The present invention relates to new acyl-piperazinyl-pyrimidines of the general formula (I), to their physiologically acceptable salts, to procedures for their preparation, to their application as medicaments in therapy for humans and/or as veterinary medicaments and to the pharmaceutical compositions which contain said compounds. 
The new compounds object of the present invention can be used in the pharmaceutical industry as intermediates and for the preparation of medicaments.
In our patents EP 382 637 and EP 497 659 we have described different derivatives of alkyl-piperazinyl-pyrimidines of the general formula (II) with ansiolytic and or tranquillising properties. 
European patent EP-0 115 713 refers to (piperazinyl-1)-2-pirimidines, with substituents in position 4 of piperazine, consisting of an alkylcarbonyl group, alkylcarbonyl substituted by an amino or substituted amino group, an alkylcarboxylic or alkylcarboxylate group, or a substituted carbonylalkyl group, having psycotropic activity by means of a dopaminergic mechanism.
PCT application WO 94/14779, refers to (piperazinyl-1)-4-pirimidines, with substituents in position 4 of piperazine, only consisting of linear or branched alkyl chains of up to 4 carbon atoms, optionally terminating with a phenyl group which may be substituted, having antagonist activity of the 5-HT1 receptor and which may be used in the treatment or prevention of upsets related to excessive vasodilatation;
U.S. Pat. No. 4,547,505 patent refers to new pharmacologically active compounds, whose general formulation includes a piperazine, where one of the nitrogen atoms is substituted by groups, namely pyrimidine or others, and the other nitrogen atom is replaced by a substituted acyl group, and which possesses analgesic activity.
We have now discovered that the addition of a substituent to position 4 of the pyrimide and the substitution of an alkyl radical with an acyl radical gives rise to the new compounds of general formula (I). Said compounds show useful biological properties which makes them especially useful for their use in therapy in humans and veterinary therapy. The compounds of the present invention are useful as agents which act on the central nervous system in mammals including humans. In particular, the new compounds are useful as sedatives, anti-convulsants, sleep-inducing agents and general anaesthetics.